This invention relates to a permeable wave dissipation caisson made mainly of concrete and placed on a seabed to dissipate the energy of waves passing therethrough.
Wave dissipation has been achieved thus far by using tetrapods or concrete blocks. This method has the disadvantage that the tetrapods or concrete blocks used are moved by the energy of the waves or that a multitude of such units are required for preventing such movement. This results in the increased cost therefor.
Moreover, obstruction of the movement of waves by the blocks prevents the alternating flow of seawater through the blocks, which causes corruption of the seawater.
It is true that there have been blocks having permeable structure, but they are built only of beams stretched in the shape of a box with walls inside and, therefore, there is the possibility that they may be turned round by the energy of the waves. Furthermore, the place wherein the blocks are set is dug deep by the waves, which makes a caisson unstable. The present invention is intended to provide a stable wave dissipation caisson which is not moved by the energy of the waves.
In addition, the present invention has the purpose of providing a caisson which not only improves the alternating flow of seawater therethrough but also can be utilized as a fishing rock owing to its permeable structure.
Furthermore, the present invention is intended to provide a caisson which can be piled one atop the other due to its box-shaped structure.